<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <script src="js/vue.js"></script>
    <title>Document</title>
</head>
    <body>
        <div id="app">
           {{msg}}
        </div>
        <script>
            var vm = new Vue({
                el:"#app",
                data:{ 
                    msg:'ok'
                },
                beforeMount() {
                    console.log('挂载之前')
                    console.log(this.$el.innerHTML)//通过this.$el获取el的DOM元素
                },
                mounted() {
                    console.log('挂载之后')
                    console.log(this.$el.innerHTML)
                },
            })
         </script>
    </body>
</html>